Mark Lansdale

Using memory for events in the design of personal filing systems

Abstract There is considerable interest in the question of how users can be supported in the management of large information systems. Existing systems are perceived as being difficult to use, and future systems will handle very much more information than at present, exacerbating the problem. This paper describes a prototype interface, MEMOIRS (Managing Episodic Memory for Office Information Retrieval Systems), which is designed to support the management of personal information in a new way. This approach treats a personal filing system as a history of events (of which documents are a particular type), and focuses upon users recall for those events. MEMOIRS therefore exemplifies a mnemonic support system which aims to optimize performance in two ways: It aims to improve users recall for the information they have handled; and it is also designed to exploit as much of what is recalled as possible. The rationale behind this approach is discussed and a broad specification of the system presented, with examples of MEMOIRS in use. The approach is compared and contrasted with other filing systems based upon models of human memory which are associative, rather than event-driven, in character.

Remembering about documents: memory for appearance, format, and location.

If we remember the visual appearance of documents, and other attributes such as location, then a number of new information management strategies become possible candidates for application in the design of filing systems. This paper describes a number of experiments aimed at investigating aspects of memory for documents in office settings. There is no evidence, as has previously been suggested, that automatic encoding for appearance or location of documents occurs at significant levels. The results of these experiments are more consistent with the view that visual and spatial attributes of documents are remembered in proportion to the attention paid to them when the documents are handled. The experiments also illustrate the sensitivity of this principle to the context in which subjects use documents. It is apparent that office tasks vary considerably in the extent to which subjects must pay attention to the visual and locational attributes of the documents handled. The consequences for the design of filing systems is discussed in terms of what methods for storage and retrieval can usefully be built into the design of systems.

Modeling memory for absolute location.

A model for recall of location is presented that postulates 2 encoding processes: 1 producing exact (all-or-none) recall, the other resulting in inexact recall. Exact recall is modeled as the outcome of a perceptual discrimination process, and inexact recall is modeled as the incomplete outcome of a Poisson process of information gain. The model accurately predicts levels of recall and patterns of errors in a number of experiments and articulates a lawful relationship between recall and elements of picture composition, such as the dimensions of the to-be-recalled attributes and the configuration of anchor points in the picture. This model enables a reappraisal of previous theoretical approaches to memory for location and of related studies concerned with automaticity in memory. The significance of this model as a general analytical device for the study of continuous attributes in memory is discussed.

Balancing search and retrieval in hypertext: context-specific trade-offs in navigational tool use

We compare user navigation performance using two hypertext information sites of identical node structure but embedded in different metaphors. The first is based upon the layout of a house and is consistent with Euclidean space. The second represents social links between people for which a spatial metaphor is not apparent. Search for targets within the structures, and the speed of their subsequent retrieval on a second search, is compared in a 2 × 4 × 2 factorial design manipulating: metaphor (spatial or non-spatial); navigation, tools (participants have both a site map and bookmark tool, one of these, or no tools at all) and the time pressure under which navigation is carried out (paced or unpaced). A strong main effect is found in which the spatial metaphor produces higher performance under all conditions. Similarly, time pressure has the general effect of trading-off a faster initial search with less efficient retrieval later. However, navigation tool use is highly context dependent and sometimes counterintuitive: certain conditions show poorer performance with two navigation aids than one. We argue that navigation tools are mediating structures for activities, such as bookmarking and learning the structure of the site, which represent cognitive investment for future retrieval. In this view, user performance is optimized by the balance of two potentially antagonistic conditions. First, the usability of tools and metaphor must free cognitive resources for planning; but also, the difficulty of the task and the need for planning must remain visible to the user. The implications for design are discussed.

A comparison of words and icons as external memory aids in an information retrieval task

Abstract Enrichment is a process whereby computer-based information is tagged with additional attributes which can be used in an information retrieval system to increase the speed and accuracy of access. In this way, the additional attributes act as external memory aids. Lansdale (1988a) evaluated such a system by looking at the memorability of coloured shapes, placed in different locations on a document, which were used as enrichers in a simple information retrieval task. This paper extends that study to look at memory for labels used in an identical way. Verbal and visual enriching attributes were studied under two conditions: one in which they were assigned to documents automatically by the system, and one in which the users made their own choice. Results indicate a strong trend in which recall was higher when subjects made their own selection of enriching attributes as opposed to having them selected for them. In the comparison of words and icons, there was no evidence that the modalities of the enric...

Developing practice with theory in HCI: applying models of spatial cognition for the design of pictorial databases

Abstract The design and development of large pictorial databases represents a considerable challenge to the design of effective interfaces and query mechanisms. This paper reviews a project concerned with the development of theories of spatial cognition and their application to the design of pictorial databases. The aim is to investigate the feasibility of developing query methods based upon visuo-spatial methods, and to consider the implications of this for design. The purpose of this paper is to discuss the joint enterprise of psychological experimentation and system development and to consider the impact upon each discipline of the shared aim of the project. Three main conclusions are drawn: (a) useful theories of spatial memory can be developed of general utility in the design of pictorial databases; (b) however, the analysis of tasks in which pictorial databases might be used reveals a complex picture in which the specificity of task domain and visual material is more likely to dictate issues of design than is any generic theory of visual cognition. In other words, the utility of visuo-spatial methods of database encoding and query cannot be taken for granted in pictorial databases; and finally (c) projects such as this, in which psychological knowledge is used as a motivation for design innovation, appear to represent high-risk, high-return strategies of design development.

Dilution as a Model of Long-Term Forgetting.

This article presents a model of long term forgetting based on 3 ideas: (a) Memory for a stimulus can be described by a population of accessible traces; (b) probability of retrieval after a delay is predicted by the proportion of traces in this population that will be defined as correct if sampled; and (c) this population is diluted over time by null traces that, if accessed, block retrieval. Dilution is modeled as a linear function of time and outcome of accessing memories by their temporal organization. The model is applied to 5 published experiments studying forgetting in cued recall, 4 recognition experiments, and 1 using savings methods. The model specifies the different form of the retention function in each case well and provides a principled explanation for some puzzling characteristics of forgetting without recourse to mechanisms such as decay or consolidation.

Evaluating the Fragmentation Hypothesis: The analysis of errors in cued recall

Abstract This paper investigates whether cued recall of multidimensional stimuli is all-or-none, as predicted by the Fragmentation Hypothesis (Jones, 1976); or probabilistic, as is commonly assumed in models of associative memory. To test this, composite stimuli were cued repeatedly, by each of their attributes in turn, to see whether the patterns of recall were consistent with all-or-none fragments. This test also requires a model to account for the inconsistent patterns of recall which are to be expected as a result of correct guessing. Of necessity, therefore, this paper also investigates the nature of guessing to enable the test of all-or-none recall. Two experiments are reported, both conditions of the same design and using the same pictorial stimuli. The first analysis looks at errors and seeks to discover interactions within sequences of responses. There are two stages involved. First, the most likely sources of each answer are indentified and classified according to a number of different categories of interest. Second, there is a statistical evaluation of the frequency with which these different categories occur. This analysis reveals: (a) the systematic recall of previous errors; and (b) that guesses comprising a pair of elements from the same (incorrect) stimulus occur more frequently than is expected by chance. Both processes have a systematic effect upon the pattern of correct guesses which is not predicted by the models of guessing commonly used. A model of cued recall is presented which combines the Fragmentation Hypothesis (including the assumption of all-or-none recall) with a model of guessing which hypothesises that a proportion of guesses act also as implicit cues for recall. This “memory checking” model of guessing is shown to predict the observed processes in guessing well. Overall, the combined model shows a satisfactory fit to the data, providing support for the all-or-none assertion. However, it is shown that a small proportion of inconsistent patterns of recall cannot be explained by the guessing model, and a low level of recall failure and forgetting is proposed. The recall of fragments is therefore closely approximated by all-or-none recall, but cannot be exactly so.

Two spatial memories are not better than one: evidence of exclusivity in memory for object location

This paper studies the dynamics of attempting to access two spatial memories simultaneously and its implications for the accuracy of recall. Experiment 1 demonstrates in a range of conditions that two cues pointing to different experiences of the same object location produce little or no higher recall than that observed with a single cue. Experiment 2 confirms this finding in a within-subject design where both cues have previously elicited recall. Experiment 3 shows that these findings are only consistent with a model in which two representations of the same object location are mutually exclusive at both encoding and retrieval, and inconsistent with models that assume information from both representations is available. We propose that these representations quantify directionally specific judgments of location relative to specific anchor points in the stimulus; a format that precludes the parallel processing of like representations. Finally, we consider the apparent paradox of how such representations might contribute to the acquisition of spatial knowledge from multiple experiences of the same stimuli.

COMPARING WORDS AND ICONS AS CUE ENRICHERS IN AN INFORMATION RETRIEVAL TASK

Cue enrichment is a process whereby computer based information is associated with additional cues which can be remembered and used in retrieval. In this respect, it has become particularly fashionable to consider the use of visiospatial information such as shapes, colours and locations. This study aimed to look at the memorability of these cues, and to make a formal comparison with keywords used in the same way. Both methods were studied under conditions in which the enriching cues were assigned automatically by the system, and in which the user selected them explicitly. Little difference was found between the verbal and visual cues in terms of their overall memorability, but interesting qualitative differences emerged, both between the visual and verbal modes and between the different dimensions of the visual and verbal cues.